Using deterministic replay for debugging of distributed real-time systems

Cyclic debugging is one of the most important and most commonly used activities in program development. During cyclic debugging, a program is repeatedly re-executed to track down errors when a failure has been observed. This process necessitates reproducible program executions. Applying classical debugging techniques, such as using breakpoints or single stepping, in real-time systems changes the temporal behaviour and makes reproduction of the observed failure during debugging less likely, if not impossible. Consequently, these techniques are not directly applicable to the cyclic debugging of real-time systems. In this paper, we present a novel software-based approach for the cyclic debugging of distributed real-time systems. By the online recording of significant system events, and then deterministically replaying them off-line, we can inspect a real-time system in great detail, while still preserving its real-time behaviour